BSDF simulations possible in diva4rhino ?

asked 2014-11-26 05:46:42 -0500

hema
259 ●1 ●6

updated 2014-11-26 09:43:08 -0500

Neal Kruis

4675 ●9 ●17 http://bigladdersoftware.com/

Hi,

I have a window which is specific (bsdf) and see how it impacts the daylighting inside a room. I would like to assign material to the window and run simulation in diva4rhino? Presently its a simple room with window on one side of the wall. So, I have a BSDF(.xml file) using lbnl window 7.2. and want to assign material and see its results using a graphical interface. So, can diva4rhino help me in this ? or suggest other interface?

Thanks in advance.

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answered 2015-04-13 13:36:11 -0500

gmolina

283 ●1 ●8 http://www.igd.cl/

Hello,

As far as I understand (I do not really use DIVA) it is not currently possible to use BSDF information in any Daylight Coefficient implementation (i.e. Daysim, DIVA). This is because of the method used within Radiance to perform the Daylight Coefficients calculations... something I do not really fully understand.

I have read things that make me think that "they" are working on an implementation of the 5phase method that should enable using BSDF within DIVA/Daysim... I am just gossiping, though.

As I mentioned before, I do not really use any of those programs (I usually use pure Radiance), but this is what I understand from the methods underneath.

Regarding any other options, Radiance or OpenStudio 3phase method allow using BSDF information, but I would not advice that if your BSDF is very specular.

Bye!

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answered 2015-04-15 12:15:53 -0500

rpg777
6960 ●6 ●15 http://openstudio.net/

updated 2015-04-15 12:22:14 -0500

While I cannot directly speak to Diva4Rhino's ability to use BSDFs in a daylight simulation, I wanted to respond to @gmolina's statement. BSDFs absolutely CAN be used in a daylight coefficient implementation; in fact, that requirement was the whole reason for developing the Radiance 3-phase technique, which leverages daylight coefficients. German is right in that BSDFs at the standard Klems basis (hemisphere subdivided into 145 patches) is insufficient to accurately capture really spiky distributions very well, and should not be used for glare analysis, at least.

As of v1.7.0, OpenStudio uses daylight coefficients and BSDFs with the 3-Phase Method to simulate the effects of blinds. While the user cannot specify the BSDF (generic ones for venetian blinds are used), we will be supporting user-specified BSDFs and shade control algorithms in an upcoming major release. Also, Andy McNeil has posted two excellent tutorials on using BSDFs with the 3- and 5-phase methods. His tutorials show you how to use Radiance directly to do this.

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I think this may be a question of semantics, but users shouldn't use a BSDF material primitive to describe window transmission in a one-phase / daylight coefficient simulation. If DIVA is able to use the Radiance BSDF material (which I don't think it can) I advise against using a BSDF material primitive to describe the window system in DIVA's annual calculation. But as you suggest the 3-phase and 5-phase methods were designed to do exactly this.